Genesis 38:11 - Matthew Poole's English Annotations on the Holy Bible

At thy father's house, whither he sent her from his house, that Shelah might not be insnared by her presence and conversation. So he dismissed her with a pretence of kindness, and a tacit promise of marriage to her, which he never intended to keep, as the following words imply; for he said; or rather, but he said; for the Hebrew chi oft signifies but, as Genesis 45:8 Psalms 37:20 Ecclesiastes 2:10, Ecclesiastes 6:2. So here is an opposition between what he said to Tamar, and what he said to himself, or in his own heart, as that word said is oft used: he intimated to her that he would give Shelah to her, but he meant otherwise, and said in himself, I will not do it, lest peradventure he die also as his brethren did; imputing the death of his two sons either to her fault, or to her unluckiness, rather than to his own or his son's miscarriages.